The present invention relates to a blow-by gas processing apparatus provided in an internal combustion engine provided with a supercharger.
A vehicle internal combustion engine can be provided with, for example, a blow-by gas processing apparatus. The blow-by gas processing apparatus recirculates a combustion gas leaking to a crank chamber from a gap between a cylinder and a piston of the engine, that is, a blow-by gas to an intake passage. Specifically, an intake negative pressure generated in a portion of the intake passage in a downstream side of a throttle valve draws the blow-by gas in an interior of the engine so as to flow into a breather passage. The blow-by gas is returned to the intake passage from the breather passage, is again fed to the combustion chamber, and is burned. Accordingly, it is possible to reduce a discharge amount of hydrocarbon (HC) to the atmosphere. Further, it is possible to inhibit the blow-by gas from deteriorating oil in the interior of the engine. As mentioned above, the blow-by gas processing apparatus ventilates the interior of the engine.
However, in the case that the supercharger is provided in the engine, if the supercharger is operated, the intake negative pressure is lost. Japanese Laid-Open Patent Publication No. 2001-164918 discloses a gas pump provided in a breather passage, however, no supercharger is provided in the engine in the publication.
An objective of the present invention is to provide a blow-by gas processing apparatus which efficiently ventilates the interior of an engine.
In accordance with one aspect of the present invention, a blow-by gas processing apparatus applicable to an internal combustion engine is provided. An intake passage extends from the engine. Intake air flows from an upstream side to a downstream side in the intake passage, whereby the intake air flows toward the engine. A supercharger and a throttle valve are arranged in the intake passage. A throttle valve is positioned downstream of the supercharger. The supercharger pressure feeds the intake air flowing through the intake passage toward the engine, thereby supercharging the intake air to the engine. The throttle valve variably sets a passage cross-sectional area of the intake passage. The intake passage has an upstream portion, an intermediate portion, and a downstream portion. The upstream portion is positioned upstream of the supercharger. The intermediate portion is positioned between the supercharger and the throttle valve. The downstream portion is positioned in a downstream side of the throttle valve. The processing apparatus has a first breather passage, a second breather passage, and an introduction passage. The first breather passage connects the interior of the engine with the downstream portion. The first breather passage has a one-way valve allowing only a gas discharge from the interior of the engine to the intake passage. The second breather passage connects the interior of the engine with the intake passage. The second breather passage has a pump pressure feeding the gas to the intake passage from the interior of the engine. The introduction passage connects at least one of the upstream portion and the intermediate portion with the interior of the engine.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.